Minecraft Server Port Forwarding Help?!

Hey I made a Spigot Server and i port forwarded it but I'm not sure why no one else can join. Please help me. I aint entering any IP in the server.properties and I dont even know what to do. I have also tried disabling my Firewall and making my friend do so too. Still, he couldn't join… I once made everything perfect with my previous ISP but now i switched to a USB mobile network called Warid. Its Configuration site is EXACTLY like that of the Huawei E5776 so please help me and ask me whatever you want about this.
Thanks

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